We
are a research group in the Physics Department of Vanderbilt
University specializing in nanoscale electronics and optoelectronics. Our
main focus is two-dimensional atomic crystals – a recently discovered class of
materials that are only atoms thick. These include: graphene, atomically
thick form of carbon with record electrical conductivity, thermal conductivity,
and strength; monolayer transition metal dichalcogenides (MoS2, WSe2, MoSe2),
semiconductors strongly interacting with light, and monolayer boron nitride
(BN), an atomically-smooth insulator material. Our overarching goal is to
answer the following questions:

How
does one controllably create, pattern, and manipulate two-dimensional atomic
crystals? Is it possible to manipulate properties of these materials by cutting
them or by stacking them into heterostructures?

What happens to interacting electrons that are confined in two dimensions
and are governed by the laws of quantum mechanics? How do they interact with
light? Is it possible to create electronic circuitry and optoelectronic devices
that are based on graphene and other two-dimensional atomic crystals?

What are the mechanical properties of atomically-thick
materials? Can we use nanoelectromechanical devices based on graphene to sense
ultrasmall forces and weigh ultralight objects?

We are equally interested in potential applications of our
research. We would like to explore the potential of graphene and other
two-dimensional materials towards applications in electronics; design
nanoelectromechanical mass and force sensors capable of weighing individual
atoms; create graphene biosensors for biomedical applications. A big part of our research is nanoscale fabrication. We use the
facilities at Vanderbilt Institute of Nanoscale Science and Engineering and Oak Ridge National Laboratory to make, contact, cut, fold, and stack with atomic precision various
two-dimensional materials from graphene to boron nitride.

Recent highlights of group’s work:

Excitons in monolayer MoS2. We demonstrated electrical and
mechanical modulation of bound electron/hole pairs, or excitons, in monolayer MoS2. The work is published in
Nano Letters and Solid State Comm.

Probing liquids at the nanoscale with graphene FETs. We
showed that transistors made of single sheets of graphene can be used to
electrically interrogate nanoscale volumes of liquid. The work is published in
Nature Communications and Nano Letters. Press coverage: Vanderbilt News

Quantum transport in ultrahigh mobility graphene. We fabricated
suspended monolayer graphene specimens, demonstrated ultrahigh mobility in these
devices, and observed the Fractional Quantum Hall Effect in graphene. The work in
published in Nature. Press coverage:Nature News and Views,PhysOrg,ScienceDaily

Nanomechanics of graphene. We probed mechanical properties of single sheets of graphene and used graphene resonators to weigh tiny masses. The work is published in Nature Nanotechnology and Nano Letters.

We gratefully acknowledge funding from:

National Science Foundation

Office of Naval Research

Defense Threat Reduction Agency

Sloan Foundation

Vanderbilt University

Open positions:Currently
looking for motivated graduate and undergraduate students to work on electronic
properties and device applications of graphene! Contact me via
email/chat or simply stop by my office if interested.

The group: Internal group site (to track projects
progress and to share relevant information). Ask me if you need to get access
to it!